Which is the correct way to set a build .env

I would like to configure a C/C++ project with some environment variables:

• Path to the compiler
• Product to build
• C/C++ defines
• ...

I currently have a custom script that I called ./configure which has nothing to do with autotools. I used it like with arguments:

$ cd project
$ ./configure --product=foo --compiler=new

This configure will setup a C header file, and some Makefiles files that will be included with the -include directive.

I've recently found a somehow better solution involving a .env script that needs to be sourced:

$ cd project
$ echo All is done with autoenv

The autoenv script does the trick. Unfortunately I am not sure this way is the correct way to work. Especially that I will need to remove all the environment variables that I put on my $PATH when I leave the project.

What is the common way to deal with that issue?

Some hints about my configuration:

• Running on Git
• Using a proprietary compiler
• Using make and Python

One possible solution that I've come across is to instanciate a new shell with the environnment set on it. A problem may appear if I forgot to exit the environment when I leave the project.